One of the earliest types of engines for performing work such as driving a load is the steam engine and at one time virtually all such engines were steam driven. While such steam engines performed satisfactorily in spite of their relatively low efficiency, subsequent developments in engine design produced engines of greater efficiency and higher horsepower to weight ratios such as the internal combustion engine, the steam turbine and the like. As a result, the use of steam engines became more and more rare so that today one seldom sees steam engines of these earlier types.
With the development of the motor vehicle, efforts were made to incorporate such a steam engine as the power unit for the vehicle but such efforts were short lived due to a number of difficulties and thus the internal combustion engine rapidly became the accepted power unit for the motor vehicle. As a result of such widespread acceptance for the internal combustion engine or gas turbine engine the steam engine as a power unit has been virtually eliminated from industrial and transportation use. Accompanying such lack of interest in the steam engine was the bringing of research and development of steam engines to a virtual stand still. However, there has been a renewed interest in steam engines as a result primarily of environmental and pollution considerations and from the continuing rise in the price of fossil fuels such as oil.
The following patents are representative of the prior art to which the subject invention pertains all of which are clearly distinguishable both structurally and functionally from applicant's steam engine:
1,160,445 Patitz, 2,295,962 Mueller, 1,440,623 Parente, 2,730,996 Doble, 1,690,129 Nielebock, 3,995,531 Zibrun, 1,962,986 Dole.
The steam engines described in the prior art patents listed above incorporate some elements which are similar in construction to some of the elements of the subject invention. However, none of these prior art engines disclose the specific new and novel combination of elements by means of which the new and unexpected results are obtained in accordance with applicant's invention.